Graft Copolymerization Of Acrylic Acid Research Articles

Synthesis, characterization and swelling behavior of superabsorbent wheat straw graft copolymers

Swelling behavior is an important characteristic for superabsorbents. A wheat straw-based superabsorbent (WS-SAB) was prepared by graft copolymerization of acrylic acid, acrylic amide and dimethyl diallyl ammonium chloride onto the cellulose of wheat straw, and its swelling and deswelling behavior was investigated. The product had a water absorbency of 133.76g/g in distilled water and 33.83g/g in 0.9wt.% NaCl solution. Fourier transform infrared spectroscopy and scanning electron microscopy indicated that the monomers were successfully grafted onto the wheat straw. The largest swelling capacity was at pH 6. The effect of ions on the swelling was in the order: Na+>K+>Mg2+>Ca2+ and Cl->SO42-. The swelling capacity did not change after several times of water absorption and release.

Removal of Mercury by an Aminated Fiber Prepared by Irradiation Grafting Copolymerization

A chelating fiber having amine functional group with high adsorption capacity for mercury ions was synthesized by grafting copolymerization of acrylic acid onto polypropylene fiber, consequently aminating with diethylenetriamine. The content of the amine groups of the chelating fiber and its adsorption capacity for mercury ion was evaluated. Isotherms were fitted by the Langmuir model, implying that the interaction between mercury and the adsorbent is mainly monolayer chelating adsorption. A comparison of the experimental adsorption capacity with the theoretical values of the chelating fibers indicated that the adsorption of the fiber for mercury ions in aqueous solution may involve ion exchange of carboxyl groups on the chelating fiber with mercury ions, besides the chelating adsorption of amine groups with mercury ions. The maximum adsorption capacity for mercury based on the Langmuir model is as high as 5.19 mmol/g. 99% removal efficiency would be achieved when feed concentration of mercury was 1 mg/L. The chelating fiber shows much higher adsorption capacity for mercury when pH value was higher than 3. The thermodynamic data indicated that the adsorption follows an endothermic and spontaneous process at solid/solution interface. Adsorption equilibrium was attained rapidly in 50 min. These results indicate that the chelating fiber is effective in practical treatment of mercury wastewater.

Fast removal of Pb2+ from water using new chelating fiber modified with acylamino and amino groups

Abstract The graft copolymerization of acrylic acid (AA) onto polyethylene glycol terephthalate (PET) fiber initiated by benzoy peroxide (BPO) was carried out in heterogeneous media. Moreover, modification of the grafted PET fiber (PET-AA) was done by changing the carboxyl group into acylamino and amino groups through the reaction with ethylenediamine. The new modified chelating fiber (NDWJN6) was characterized using elementary analysis, SEM and FT-IR spectroscopy. Adsorption kinetic curve indicated that NDWJN6 could fastly remove Pb 2+ from water, and adsorption isotherm also indicated that NDWJN6 had high equilibrium adsorption capacity for Pb 2+ .

Preparation of superabsorbent based on the graft copolymerization of acrylic acid and acrylamide onto konjac glucomannan and its application in the water retention in soils

AbstractA new konjac glucomannan (KGM)‐based superabsorbent polymer, KGM‐g‐poly(acrylic acid‐co‐acrylamide), was prepared by the free radical grafting solution polymerization of acrylic acid (AA) and acrylamide (AM) monomers onto KGM in the presence of N,N′‐methylenebisacrylamide as a crosslinker with potassium persulfate as an initiator. The effects of reaction parameters, including the amount of crosslinking agent and initiator, the weight ratio of both (AA + AM) to KGM and AM to (AA + AM), neutralization degree of AA, bath temperature, and reaction time, on the water absorbency of the superabsorbent were investigated. The Fourier transform infrared spectroscopy was used to characterize the structures of the copolymer. The maximum water absorbency of the optimized product was 650 g/g for distilled water and 70 g/g for a 0.9 wt % aqueous NaCl solution. Furthermore, the water retention of the copolymer in soils was studied. The effect of the copolymers on the aggregate distribution of soils was also evaluated. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Study of Graft Copolymerization of Acrylic Acid Onto Nata De Coco and its Application as Microfiltration Membrane

Chemical and physical modifications of membrane can be carried out by radiation induced graft copolymerization. The aim of this research is to prepare graft copolymers of acrylic acid onto nata de coco (NDC-g-AAc) by radiation and to study the performance of grafted copolymer as microfiltration membrane. Using a total dose of 30 kGy, the highest degree of grafting obtained were 209% and 142% for r (weight ratio of monomers to nata de coco) equal to 61.3 and 35.7 respectively. The increasing degree of grafting resulted in decreasing flux due to high hydrogen bonding between grafted acrylic groups and water. It was found that the degree of swelling of NDC-g-AAc membrane with r = 35.7 was higher than that of r = 63.1. The changes of chemical structure of membrane were characterized by FTIR spectroscopy which showed a new band at 1720 cm -1 attributed to the carbonyl group of acrylic acid

Ce(IV) Ion–Initiated and Microwave Radiation–Induced Graft Copolymerization of Acrylic Acid onto Lignocellulosic Fibers

The present work deals with the graft copolymerization of acrylic acid onto natural Cannabis indica fiber by using Ce3+-HNO3 redox initator system under the influence of microwave radiation (MWR). The reaction conditions such as time, initator concentration, monomer concentration, nitric acid concentration, and pH were optimized to get the maximum percentage of grafting (9.86%). The graft copolymers thus formed were characterized by FT-IR, X-ray diffraction, thermogravimetric analysis, and scanning electron microscope techniques. Raw Cannabis indica fiber and graft copolymerized fibers were also subjected to evaluation of some of their properties like swelling behavior, moisture absorbance, and resistance towards chemicals.

Thermal and electrical properties of acrylic acid grafted onto starch by ceric ammonium nitrate and potassium permanganate initiator

Graft copolymerization of acrylic acid (AA) onto corn starch (Starch) in aqueous media via a redox initiator system of ceric ammonium nitrate and potassium permanganate has been studied gravimetrically under nitrogen atmosphere. The grade of graft copolymers were synthesized under the effect of reaction variables such as redox initiator concentration, monomer concentration, reaction temperature and polymerization time on the grafting were studied in terms of percent grafting ratio (% G) and percent grafting efficiency (% E). The graft copolymers obtained were characterized by fourier transform infrared (FTIR), scanning electron microscope (SEM), and thermogravimetry analysis (TGA). SEM morphology shows that the surface of the grafted starch is highly rough in comparison with ungrafted starch which is attributed to the high graft density. The starch surface was dispersed heterogeneously among the polyacrylic matrix and rugged surface was observed that all fragments of these surfaces are rough, spherical, rod in shape. The FTIR shows characterized peak in the region 1722.28 cm−1 which attributed to the shift in the position of C = O group deriving grafting of AA with starch. TGA shows the graft copolymer degrades at higher temperature and electrical conductivity indicates conductivities lies between 10−7 and 10−5 S/cm.

Fast removal of heavy metal ions and phytic acids from water using new modified chelating fiber

Abstract The graft copolymerization of acrylic acid (AA) onto polyethylene glycol terephthalate (PET) fiber initiated by benzoy peroxide (BPO) was carried out in heterogeneous media. Moreover, modification of the grafted PET fiber (PET-AA) was done by changing the carboxyl group into acylamino group through the reaction with dimethylamine. The modified chelating fiber (NDWJN1) was characterized using elementary analysis, SEM and FT-IR spectroscopy. Adsorption kinetic curves indicated that NDWJN1 could fast remove heavy metal ions and phytic acids from water effectively. Furthermore, batch kinetic studies indicated that heavy metal ions adsorbed to NDWJN1 could be fitted well by both pseudo-first-order and pseudo-second-order adsorption equations, but the intra-particle diffusion played a dominant role in the adsorption of phytic acids.

Xylan-rich Hemicelluloses-graft-Acrylic Acid Ionic Hydrogels with Rapid Responses to pH, Salt, and Organic Solvents

Exploitation of biomaterials derived from renewable resources is an important approach to address environmental and resource problems in the world today. In this paper, novel ionic hydrogels based on xylan-rich hemicelluloses were prepared by free radical graft copolymerization of acrylic acid (AA) and xylan-rich hemicelluloses (XH) by using N,N-methylene-bis(acrylamide) (MBA) as cross-linker and ammonium persulfate/N,N,N',N'-tetramethylethylenediamine (APS/TMEDA) as redox initiator system. The network characteristics of the ionic hydrogels were investigated by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM), as well as by determination of mechanical properties, swelling, and stimuli responses to pH, salts, and organic solvents. The results showed that an increase in the MBA/XH or AA/XH ratio resulted in higher cross-linking density of the network and thus decreased the swelling ratio. Expansion of the network hydrogels took place at high pH, whereas shrinkage occurred at low pH or in salt solutions as well as in organic solvents. The ionic hydrogels had high water adsorption capacity and showed rapid and multiple responses to pH, ions, and organic solvents, which may allow their use in several areas such as adsorption, separation, and drug release systems.

Microwave-Irradiated Preparation of Super Absorbent Resin by Graft Copolymerization of Starch and Acrylic Acid

Graft copolymerization of acrylic acid(AA) on starch to prepare super absorbent resin (SAR) under microwave irradiation were investigated using N,N-methylene bis-acrylamide as crosslinker and potassium persulfate as initiator. The influences of the amount of initiator and crosslinker, neutralization degree of acrylic acid(AA), ratio of starch to AA, microwave power level and irradiation time on the distilled water absorption amount of resin were investigated. The results indicated that it only needed 4min under the microwave level of 231W to obtain the resin with the maximum absorption amount of 1110g×g-1, under the conditions that 0.3wt% initiator, 0.02wt% crosslinker, 60% neutralization degree of acrylic acid, the ratio of starch to acrylic acid of 0.25. Under microwave irradiation, the synthesis and drying of super absorbent resin could be completed at one step without nitrogen. Compared to conventional heating method, the methods had the striking advantages of short reaction time, simple process and low cost.

Pb(<i>II</i>)-Imprinted Polymer Prepared by Graft Copolymerization of Acrylic Acid onto Cellulose

The Pb( )-imprinted polymers were synthesized through homogeneous graft copolymerization of cellulose with acrylic acid in an homogeneous medium using Pb( ) as template. The prepared copolymers were characterized by FTIR and SEM. The batch adsorption experiments were conducted to evaluate the adsorption capacity of the Pb( )-imprinted beads. The results demonstrated that the imprinted beads showed significantly higher imprinting efficiency than those only consisting of poly(acrylic acid) without Pb( )-imprinted, and the selectively adsorption capacity of Pb( ) on imprinted beads was higher than other competitive ions(Cu( ) or Ni( )). The imprinted beads also showed much better stability in rebinding of the imprinted ions after three adsorption-regeneration cycles.

Adsorption Behavior of L-Histidine on a Novel Spherical Chitosan Adsorbent

The spherical chitosan adsorbent was prepared by graft copolymerization of acrylic acid onto the cross-linked spherical chitosan beads, and then was adopted to adsorb the L-histidine. The adsorption conditions, i.e., solution pH, adsorption time, initial concentration and adsorption temperature were optimized. The spherical chitosan adsorbent showed excellent equilibrium adsorption capacity of 78.3 mg/g for the L-histidine when the solution pH value was 7.5, adsorption time was 180 min, initial concentration was 1500 mg/L and the adsorption temperature was 25 °C. Moreover, the inorganic salt of NaCl also showed great effect on the equilibrium adsorption capacity exceeding 0.8 mol/L. The static adsorption processes followed the Langmuir adsorption isothermal equation and Freundlich adsorption isothermal equation. Furthermore, L-histidine could be desorbed with 1.5 mol/L of ammonia solution, and the regeneration capacity of the spherical chitosan adsorbent was excellent.

Surface Modification of PET Fabric by Graft Copolymerization with Acrylic Acid and Its Antibacterial Properties

Graft copolymerization of acrylic acid (AA) onto Poly(ethylene terephthalate) (PET) fabrics with the aid of benzoyl peroxide was carried out. The effect of polymerization parameters on the graft yield was studied. Percent grafting was enhanced significantly by increasing benzoyl peroxide (BP) concentrations up to 3.84 g/lit and then decreased upon further increase in initiator concentration. Preswelling of PET leads to changes in its sorption-diffusion properties and favors an increase in the degree of grafting. The antibiotics treated grafted fabrics showed antibacterial properties towards gram-positive and gram-negative microorganisms. FTIR and SEM were used to characterize AA-grafted polyester fabrics.

Preparation and Properties of Carrageenan-g-Poly(Acrylic Acid)/Bentonite Superabsorbent Composite

A novel biopolymer-based superabsorbent hydrogel composite based on kappa-carrageenan (κC) have been prepared via graft copolymerization of acrylic acid (AA) in the presence of bentonite powder using methylenebisacrylamide (MBA) as a crosslinking agent and ammonium persulfate (APS) as an initiator. The hydrogel structure was confirmed using FTIR spectroscopy and the morphology of the samples was examined by scanning electron microscopy (SEM). The affecting variables onto graft polymerization (i.e. AA, MBA and APS concentration, as well as the bentonite amount) were systematically optimized to achieve a hydrogel with swelling capacity as high as possible. The results of Brunauer–Emmett–Teller (BET) analysis showed that the average pore diameter of the synthesized hydrogel was 11.5 nm. The effect of various salt media and solutions with different pHs on the swelling of the superabsorbent was also studied.

UV-prepared salep-based nanoporous hydrogel for controlled release of tetracycline hydrochloride in colon

A highly swelling nanoporous hydrogel (NPH) was synthesized via UV-irradiation graft copolymerization of acrylic acid (AA) onto salep backbone and its application as a carrier matrix for colonic delivery of tetracycline hydrochloride (TH) was investigated. Optimized synthesis of the hydrogel was performed by the classic method. The swelling behavior of optimum hydrogel was measured in different media. The hydrogel formation was confirmed by Fourier transform infrared spectroscopy (FTIR) and thermo-gravimetric analysis (TGA/DTG/DTA). The study of the surface morphology of hydrogels using SEM showed a nanoporous (average pore size: about 350 nm) structure for the sample obtained under optimized conditions. The drug delivery results demonstrated that this NPH could successfully deliver a drug to the colon without losing the drug in the stomach, and could be a good candidate as an orally administrated drug delivery system.

Synthesis and swelling behaviors of sodium carboxymethyl cellulose-g-poly(AA-co-AM-co-AMPS)/MMT superabsorbent hydrogel

Superabsorbents were synthesized by graft copolymerization of acrylic acid (AA)/acrylamide (AM)/2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) onto sodium carboxymethyl cellulose (CMC) and montmorillonite (MMT) by using potassium persulfate (KPS) as a free radical initiator, in the presence of N,N′-methylenebisacrylamide (MBA) as a crosslinking agent. The structure and morphologies of the superabsorbents were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). Superabsorbent comprised a porous crosslink structure of MMT and CMC with side chains that carry carboxylate, carboxamide and sulfate. The swelling behaviors of the superabsorbent were dependant on the pH of external solutions, particle size and the concentration of the salt solution. The effect of four cationic salt solutions on the swelling had the following order: K+>Na+>Ca2+>Mg2+.

Synthesis and characterization of a novel super-absorbent based on wheat straw

In order to develop an eco-friendly polymer, a novel super-absorbent polymer was prepared by graft copolymerization of acrylic acid (AA), acrylic amide (AM) and dimethyl diallyl ammonium chloride (DMDAAC) onto the pretreatment wheat straw (PTWS). The molecular structure of the super-absorbent was confirmed by FTIR. The factors that can influence absorbencies of the super-absorbent resin (SAR) were investigated, such as weight ratio between the monomers, the ratio of PTWS to monomers, the amount of initiator and cross-linker, temperature reaction time and neutralization degree of AA. The SAR has the water absorbency of 133.76 g/g in distilled water and 33.83 g/g in 0.9 wt.% NaCl solution.

Microwave-Irradiated Preparation of Super Absorbent Resin by Graft Copolymerization of Cellulose and Acrylic Acid/Acrylamide

Graft copolymerization of acrylic acid(AA) and acrylamide(AM) on cellulose to prepare super absorbent resin (SAR) under microwave irradiation were investigated using N,N-methylene bis-acrylamide as crosslinking agent, and potassium persulfate/sodium thiosulfate as initiator. The results indicated that it only needed 5min under the microwave level of 320W to obtain the resin with the maximum absorption amount of 1388g•g-1 , under the conditions that the ratio of acrylic acid to cellulose of 14:1, 0.25wt% initiator to AA, 0.25wt% crosslinking agent, 70% neutralization degree of AA. Under microwave irradiation, the preparation of SAR could be completed without the protection of nitrogen. Compared to conventional heating method, the methods had the striking advantages of short reaction time, simple process and low cost.

Gamma irradiation mediated synthesis of a new superabsorbent hydrogel network based on poly(acrylic acid) grafted onto salep

A novel and smart biopolymer-based hydrogel was synthesized by graft copolymerization of acrylic acid onto the salep backbones. The new superabsorbent hydrogel was synthesized via simultaneous crosslinking and graft copolymerization of acrylic acid (AA) monomer onto salep backbones using radiochemical methods. In radiochemical methods, γ-rays as initiator, energy source and crosslinker are applied. In our experiments, the effects of reaction variables such as relative contents of salep and AA, as well as γ-rays total dose were examined. According to water absorbency of the entitled network, the best synthesis condition is reported. FTIR spectroscopy, SEM photograph and TGA analysis were used for confirming the structure of the final product and a mechanism for superabsorbent hydrogel formation is also suggested. Furthermore, in this research, several factors affecting the swelling behavior of hydrogel including pH of medium, sensitivity to the salt solution and mixture of solvents were studied.

A comparative study on the graft copolymerization of acrylic acid onto rayon fibre by a ceric ion redox system and a γ-radiation method

Functionalization of rayon fibre has been carried out by grafting acrylic acid (AAC) both by a chemical method using a Ce 4+–HNO 3 redox initiator and by a mutual irradiation (γ-rays) method. The reaction conditions affecting the grafting percentage have been optimized for both methods, and the results are compared. The maximum percentage of grafting (50%) by the chemical method was obtained utilizing 18.24 × 10 −3 moles/L of ceric ammonium nitrate (CAN), 39.68 × 10 −2 moles/L of HNO 3, and 104.08 × 10 −2 moles/L of AAc in 20 mL of water at 45 °C for120 min. For the radiation method, the maximum grafting percentage (60%) was higher, and the product was obtained under milder reaction conditions using a lower concentration of AAc (69.38 × 10 −2 moles/L) in 10 mL of water at an optimum total dose of 0.932 kGy. Swelling studies showed higher swelling for the grafted rayon fibre in water (854.54%) as compared to the pristine fibre (407%), while dye uptake studies revealed poor uptake of the dye (crystal violet) by the grafted fibre in comparison with the pristine fibre. The graft copolymers were characterized by IR, TGA, and scanning electron micrographic methods. Grafted fibre, prepared by the radiation-induced method, showed better thermal behaviour. Comparison of the two methods revealed that the radiation method of grafting of acrylic acid onto rayon fibre is a better method of grafting in comparison with the chemical method.